The weather map one sees on television exists as an image stored in a computer. The image does not appear on a blank, typically blue screen behind the weatherman in studio. Before transmission to the home viewer, the blue screen is electronically removed and replaced by the weather map. The weatherman""s view of the weather map is displayed on a monitor just beyond the edge of the blue screen. On this monitor he observes the position of his hand over the map. He moves his hand over the blue screen, so that his hand appears to be pointing to the desired area on the weather map. The home audience wonders why the weatherman looks off-screen rather than at the map that appears to be behind him, and he sometimes points to an area he is not describing. This hand-eye-screen coordination is awkward, non-instinctive, and requires practice.
In this invention a white screen replaces the blue screen. A video signal is generated representative of the background scene, such as a weather map, which provides an outline of all the detail in the map. For example, in a map of the United States, the borders of the United States and of the individual states would appear, as well as the outline of numbers and other detail. This outline detail is made visible to a foreground subject such as a weatherman by projecting it onto the white screen behind him in a selected color such as green. The projector is selectively inhibited so as to prevent the background detail from projecting onto the foreground subject. The white screen and the green detail lines are removed and replaced by the weather map by an image compositing process. The prompts are visible to the foreground subject, but not visible to the home viewing audience.
Upon looking at the white screen, the foreground subject, such as a weatherman or other presenter of information, sees all of the weather map or other information detail as green outlines. He may point quickly and accurately to any element on the weather map. The home viewer sees the presenter in front of a full color map. This process of providing a presenter with accurate and detailed prompts may be used with any background, not just weather maps.